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B Zimmermann

Publications and source records attributed to B Zimmermann.

At least 127 records · Page 7Linked to original sources
PubMed1985

Evaluation of the sensitive step of inhibition of chondrogenesis by retinoids in limb mesenchymal cells in vitro.

The sensitive step of inhibition of chondrogenesis in vitro by retinoids was investigated in modified micromass cultures of limb bud mesenchymal cells from mouse embryos of day 11 and 12. Evaluation of chondrogenesis was performed after alcian blue staining, using a simple random hit counting of cartilage nodules. All-trans-retinoic acid, 13-cis-retinoic acid, and a newly developed arotinoid, RO 13-6298, were tested for their ability to inhibit chondrogenesis. We found that inhibition of chondrogenesis depended on the dosage and the duration of treatment with the different retinoids. Further analysis showed that chondrogenesis in limb bud mesenchymal cells from the proximal part was irreversibly inhibited after one hour of treatment, whereas distal cells showed a reduction of cartilage development only after a treatment period of 12 and more hours. In respect to the doses of the retinoids, proximal cells were about one magnitude more vulnerable than distal cells. These proximo-distal differences were obtained with 13-cis-retinoic acid at 10 micrograms/ml, with all-trans-retinoic acid at 1 microgram/ml and with arotinoid RO 13-6298 with 10 ng/ml. It is supposed that the late blastemal stage of chondrogenic differentiation before the onset of matrix synthesis is the step which is most vulnerable to retinoid treatment.

Animals↗
PubMed1985

Percutaneous transhepatic catheterization in reconstructive surgery of the biliary ducts.

Preoperative placement of a No. 9 percutaneous transhepatic drainage catheter for two to three weeks greatly improves the condition of the patient who has suffered operative damage to the hepatic bile ducts. At operation the previously placed catheter serves to identify the proximal portion of the damaged bile duct, even in dense scar tissue, and then serves to pull a Silastic tube stent in a retrograde manner into the bile duct and out through the right hepatic lobe and skin. This stent is left across the hepaticojejunostomy anastomosis for 12 months, or even permanently, in cases in which the anastomosis can be made only to scar tissue rather than biliary mucosa.

Adult↗
PubMed1985

Basement membrane formation and lung cell differentiation in vitro.

In high density cultures of mouse fetal lung cells, so-called "mass cultures", development of organoid structures, formation of a basement membrane (BM), and differentiation of pneumocytes type II occur accompanied by synthesis and secretion of lamellar bodies. The relationship between the formation of a BM, on the one hand, and morphogenesis as well as differentiation of pneumocytes type II, on the other hand, has been investigated by use of antibodies against BM components in the lung mass culture. It is shown here that anti-laminin antibodies prevented BM formation, but morphogenesis and pneumocyte differentiation occurred as in untreated cultures. Short-term treatment with the antibody revealed that the BM is formed only during the first 2 to 3 days in vitro. Already formed BM could not be removed by anti-laminin. Anti-collagen type IV antibodies showed no effect in the lung mass culture except for a stronger staining of the BM. Anti-BM-1 antibodies caused no changes in morphogenesis, cell differentiation and BM formation either, but the mesenchymal intercellular space exhibited a dark staining, which is probably due to antigen-antibody complexes. The results obtained with anti-laminin antibodies indicate that a BM is not necessary for lung cell differentiation in vitro.

Animals↗
PubMed1984

Alterations of lectin binding during chondrogenesis of mouse limb buds.

The binding of six different FITC-labelled lectins to mesenchyme, blastemal cells and cartilage was investigated in limb buds of mouse embryos during their development from day 10 to day 13. Concanavalin A, wheat germ agglutinin and phaseolus vulgaris agglutinin labelled mesenchymal cells of earlier stages, day 10 or 11, distinctly more than those of later stages. Chondrogenic blastema, basement membrane and muscle were always strongly stained. The galactosamine-specific ricinus communis agglutinin (RCA) bound preferentially to the blastema, whereas the mesenchyme was only weakly labelled. The galactose-specific peanut agglutinin (PNA), however, stained solely the blastema. In the mesenchyme, no binding was detectable light microscopically with this lectin. In cartilage, RCA- and PNA-staining was found to a lesser extent. With the fucose-specific lectin Lotus A, no staining was detectable. Due to the apparent differences in the binding of PNA in mesenchyme and blastema, peroxidase-labelled PNA was used to study the binding behaviour electron microscopically. It is shown that peroxidase-PNA very strongly labelled the intercellular matrix and the plasma membrane of cells in the late blastemal stages, whereas in young blastema no reaction product was detectable. In contrast to light microscopic findings, some label could be demonstrated also in the mesenchyme. The results show a general reduction of lectin receptors in more developed mesenchyme of later stages and the occurrence of galactose and galactose derivatives during early chondrogenesis in the matrix and at the cell membrane. The significance of these changes for chondrogenesis, however, remains to be elucidated.

Animals↗
PubMed1984

Comparative accuracy of two new electronic devices for the noninvasive determination of blood pressure.

Recent developments in behavioral approaches to cardiovascular disease have called for physiological monitoring devices that reduce experimenter bias, are easy to operate, can be used ambulatorily, and/or provide ongoing, automated monitoring of pertinent cardiovascular functions--i.e., blood pressure and heart rate. Neither the invasive monitoring (via catheterization) nor the standard auscultatory method of blood pressure determination, however, has these characteristics. In the present study, two new methods/devices--(1) a low-weight, low-cost, battery-operated sphygmomanometer (SM), and (2) a more expensive automated electronic SM with electrical pump-are compared with each other and with the more common auscultatory method and a standard mercury SM. Both new devices were also compared with a standard pulse count. Data were derived from 10 readings of 10 healthy subjects each across the three possible comparisons, thus totaling N = 30. Correlation coefficients and average differences were computed and indicated high intercorrelations (between r = .89 and r = .99) between each pairing of the new electronic devices and the mercury SM. Intercorrelations of blood pressure determination with the two new electronic devices, however, were only moderate. Potential reasons for the variability are discussed, and guidelines for the optimal use of the new, easy-to-operate electronic devices are presented.

Adult↗
PubMed1984

Amino-acid sequence and disulfide linkages of the anaphylatoxin, des-Arg omega-C5a, from porcine serum.

The primary structure of the porcine complement-derived peptide, des-Arg omega-C5a, has been analysed. Des-Arg omega-C5a is the natural secondary product of the activation fragment of the fifth component of complement, C5a, and represents a classical anaphylatoxin. The elaborated amino-acid sequence confirms the structure of porcine C5a proposed earlier by Gerard and Hugli, with one exception. Further, by end-group determination and sequencing of the unreduced core of des-Arg omega-C5a the position of its three disulfide bridges has been determined, now allowing insight into the tertiary structure of des-Arg omega-C5a.

Amino Acid Sequence↗
PubMed1984

The significance of cell contacts for the differentiation of the skeletal blastema.

Isolated limb bud cells from day-11 and day-12 mouse embryos served to investigate the significance of adhesion and contact formation for triggering cartilage differentiation in the blastema. In monolayer culture at low cell density, fibroblastlike cells developed which produced collagen type I and pro III as well as fibronectin. In mass culture at high cell density, however, cartilage tissue formed whose matrix contained collagen type II and cartilage-specific proteoglycans. Other experiments showed that the existence of an overgrowth phenomenon and a cartilage-inducing factor is not the reason for differentiation differences. An increased adhesion tendency and the occurrence of gap junctions speak for changes in the cell membrane during blastema formation. These notions are supported by investigations using fluorochrome-labelled lectins which show that sugar chains with terminal galactosyls only exist during the blastemal stage. It is assumed that adhesion gives the signal for chondrogenesis. The differentiation signal is then stabilized and passed on through cellular communication via gap junctions. After the onset of chondrogenesis, the cell membrane changes again and the gap junction-containing segments are incorporated and disaggregated.

Animals↗
PubMed1984

Assembly and disassembly of gap junctions during mesenchymal cell condensation and early chondrogenesis in limb buds of mouse embryos.

During early chondrogenesis of the limb skeleton, cell condensations occur which are characterised by an increased density of cell packing, a decrease in the extent of the intercellular space and a drastic increase in the number of gap junctions. Electron microscopical investigations have been performed on the assembly and disassembly of these gap junctions in limb buds of mouse embryos during Days 10-12 of pregnancy. In undifferentiated mesenchyme, focal cell contacts occurred showing a gap of about 10 nm between adjacent cell membranes. During further development these contacts became broader, the intercellular gap decreased to 5 nm and gap junction structures were first formed at the ends of such cellular contacts. At the stage of maximum cell condensation, the blastemal cells were interconnected by large gap junctions, but there were also a considerable number of coiled gap junction structures present intracellularly. Near these coiled gap junctions, a well developed Golgi apparatus and many coated vesicles were generally detectable, indicating a fast turnover of cell membrane. The results suggest an insertion of gap junction components into the membrane during contact formation. Deposition of new cell membrane and coiling and invagination of gap junctions are discussed in the context of cell separation at the beginning of chondrogenesis.

Animals↗
PubMed1982

Basement membrane alterations after treatment with trypsin, hyaluronidase or collagenase.

A transplantable rodent tumor producing multiple layers of basement membrane was used to study the effects of trypsin, hyaluronidase and collagenase on basement membranes. Treatment with trypsin resulted in an increase in the distance between adjacent lamellae and a loss of granular structures. Treatment with hyaluronidase separated basement membrane layers only in the outer lamellae, whereas collagenase resulted in extensively folded sheets which consisted predominantly of granules. From these findings it may be concluded that the granular structures represent the morphological equivalent of glycoproteins which are interlinked by a collagenous filamentous network. Hence, the BM represents a functional unit of proteoglycans, glycoproteins and collagen.

Animals↗
PubMed1982

Cell contact and surface coat alterations of limb-bud mesenchymal cells during differentiation.

Measurements of the cell perimeter, cell-cell contact number and length and of the thickness of the surface coat were performed in limb buds of mouse embryos during the process of cell condensation of the chondrogenic cell mass. This study starts with measurements of 'non-limb' mesenchyme of day-9 embryos and ends with the young cartilage of day 13. It is shown that until day 12 all cells in the limb bud are interconnected by cell contacts of the gap-junction type. Contact number and contact length increase during development, but increase about twice as much between central, prechondric cells as between peripheral or distal cells. Later in development, chondroblasts lose their contacts almost completely, whereas between peripheral cells, the amount of cell contacts drops to the initial value of mesenchymal cells. The cell size decreases during chondrogenesis. A decrease in the thickness of the surface coat of the cells during the whole differentiation period is shown. It may be assumed that this 'wave of cell contacts' is the last step for the initiation of the chondrogenic differentiation process.

Animals↗
PubMed1981

Isolation and properties of a complement inhibitor from Naja haje venom, distinct from known anticomplementary factors in cobra venom.

A complement inhibitor (CI) has been isolated from cobra (Naja haje) venom which is distinct from the two known anticomplementary factors in cobra venom [1], in functional properties as well as structure. CI is a small (mol. wt 26,000, determined by sodium dodecyl sulphate gel electrophoresis), heat-labile glycoprotein; the amino acid composition is that of a globular protein. CI interferes at various steps of the complement sequence, including reactions of the classical and alternative pathway. No effect was observed on C4 fixation and on the assembly of the membrane attack complex from C6-9 (minor inhibiting effects, if present, have not been excluded). Initiation of the alternative pathway is inhibited by CI already at the stage of cleavage of factor B. CI binds to C4, C4b, C3 and C3b; since the major inhibitory action of CI is lost after washing of cell intermediates, complex formation and, as a consequence, steric hindrance may be responsible for the inhibiting effects of CI. CI also interferes with binding of C3b to C3b receptors on human erythrocytes. CI is non-toxic in mice when given intraperitoneally in doses of 5 microgram/g.

Amino Acids↗
PubMed1981

[Incidence of female gonorrhoea in relationship with inflammatory gynaecological diseases - verification from cultures (author's transl)].

Gonorrhoea was detected in 7.3 per cent of 423 patients with gynaecological inflammations. Positive findings were recorded from 8.5 per cent of 248 patients with adnexitis and 6.9 per cent of 130 patients with fluor. However, gonorrhoea incidence among 31 patients with pointed condyloma was as low as 3.2 per cent. These findings were found to differ drastically from the data so far obtained from the common approach of microscopic diagnosis by which hardly any positive detection of gonococci had been recordable from gynaecological out-patients over the years. The present considerable rise in positive findings has resulted only from the use of a modified transport medium, according to Stuart, which proved to be highly applicable to gynaecological practice. With the authors' patients, the new approach showed the presence of gonorrhoea in one of 14 patients with inflammatory gynaecological processes. Against the background of the present epidemiological situation, verification of gonococci from cultures should be made an integral component of gynaecological routine checks.

Adolescent↗
PubMed1981

Coarctation of the thoracic aorta: an 18-year experience.

From 1960 to 1978, 80 patients from 2 weeks to 49 years of age underwent operations for coarctation of the aorta. Twelve patients were under 3 months old, and 68 were older. All of the infants presented with congestive heart failure and multiple cardiac defects. In the older patients, hypertension was the most common presenting symptom; 14 were asymptomatic. All patients under 3 months old received primary correction. Seven (58%) died of complications associated with other cardiac anomalies. In the older group, there was 59 primary reconstructions, six interposition grafts, and three other procedures. There were two deaths in this group. There were three re-explorations, two for bleeding and one for false aneurysm at the suture line. Seven older patients exhibited paradoxical hypertension: three developed abdominal symptoms and two required laparotomy. Three patients originally operated on during infancy developed recurrent coarctation with reoperation in two. Nine of the older patients had chronic hypertension, all of whom were operated on after age 15. Surgical correction of coarctation in infants carries a high mortality rate secondary to associated defects. The operative mortality rate in older patients is minimal, and correction should be undertaken early to prevent the long-standing complications of hypertension.

Adolescent↗
PubMed1980

Behaviour of epiphyseal mouse chondrocyte populations in monolayer culture. Morphological and immunohistochemical studies.

Growth and dedifferentiation of a heterogeneous mouse chondrocyte population, prepared from epiphyses of mouse embryos (day 17 of gestation), were studied in primary monolayer culture. At different times of culture, light and electron microscopic investigations were carried out and the change of collagen types was shown by immunofluorescence microscopy. During the first four days in culture, chondrocytes express their typical phenotype. Round or polygonal cells are embedded in a metachromatically staining matrix and produce type II collagen. After four to eight days in vitro most of the chondrocytes lose their matrix capsule and alter to fibroblast-like cells. Simultaneously, a switch of collagen synthesis to type III and type I collagen occurs, whereas the type II collagen synthesis is stopped. Altered cells and transitional stages have intracellular glycogen like typical chondrocytes, but show phagocytosis and indications of cell migration like fibroblasts. It is proposed that these cells, originating from a subpopulation of epiphyseal cartilage, are able to differentiate and dedifferentiate in vitro.

Animals↗
PubMed1980

Biological activities of C5a and C5adesArg from hog serum.

The complement-derived peptides C5a and C5adesArg (highly purified from yeast-activated hog serum) were both active in the following biological assays: in aggregation of human leukocytes (potency ratio for C5a:C5adesArg 3:1), in aggregation of guinea pig platelets (10:1), in chemotaxis of peritoneal rabbit leukocytes (10:1), and in contraction of isolated guinea pig ileum (1.4:1). The fact that C5adesArg preparations have 30 and 40% of the activity of C5a in leukocyte aggregation and smooth muscle contraction but only 10% of C5a chemotactic activity, clearly indicates that aggregation and spasmogenic activity are inherent properties of C5adesArg. Evidence that C5adesArg owns all activities studied is further given by the following findings: chromatographic separation of mixtures of C5a and C5adesArg results in the appearance of two peaks of spasmogenic activity; treatment of C5adesArg with carbopeptidase B does neither lead to release of detectable arginine nor abrogate any of the biological effects; treatment of C5a with carboxypeptidase B reduces the activities quantitatively to those of C5adesArg, and liberates the theoretically expected amount of arginine.

Amino Acids↗
PubMed1980

Purification and partial amino acid sequence of classical anaphylatoxin from pig serum: identification with Des-Arg-C5a.

Complement was activated in hog serum and the biologically active peptide(s) derived from the fifth component of complement were purified. Treatment of the serum with yeast, without any precautions to inhibit serum arginine carboxypeptidase, allowed the recovery of only one active fraction, the classical anaphylatoxin; it was identified as des-Arg-C5a. When hog serum was activated with yeast in the presence of 1M epsilon-aminohexanoic acid (inhibitor of arginine carboxypeptidase), two active C5-derived fractions were obtained, C5a and des-Arg-C5a. A partial amino acid sequence of the classical anaphylatoxin (19 N-terminal and 12 C-terminal amino acids) has been elaborated. With one exception it is identical with hog C5a as far as that structure is known (12 N-, 3 C-terminal amino acids). The only difference is the C-terminal region: arginine, present in C5a, is absent from des-Arg-C5a which ends with ... Asn-Ile-Gln-Leu-Gly-OH. The finding that des-Arg-C5a, virtually free of any significant contamination with C5a, has considerable spasmogenic activity demonstrates that it is the classical anaphylatoxin, and that for spasmogenic activity arginine as the C-terminal amino acid is not absolutely essential.

Amino Acid Sequence↗
PubMed1980

Changes in the surface coat of mesenchymal cells of mouse limb buds after enzymatic cell separation.

Isolation of cells is nowadays performed by enzymatic means. The influence of such enzymes on the surface coat of mesenchymal and blastemal cells during the dissociation of limbs buds from 11-day-old mouse embryos was studied electron microscopically after staining with ruthenium red. EGTA or collagenase failed to bring about cell separation. The surface coat seemed to be unchanged after collagenase treatment. After EGTA an increase in extracellular filaments was observed. The proteases alpha-chymotrypsin, dispase II, papain, pronase P and trypsin (0.2%, 37 degrees C, 20 min) succeeded in completely dissociating limb buds. Apart from single granules, there was a detachment of the surface coat from the cells in all cases studied. Hyaluronidase led to only partial separation, but the detachment of the surface coat was almost complete, indicating a GAG-rich surface layer on these cells.

Animals↗